Vitamins and Their Functions, Deficiencies, and Toxicities, Schemes and Mind Maps of Biochemistry

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Dr. Nguyen Thi

Hoang Yen

VITAMINS

11 - cis-retinol: component of rhodopsin Deficiency: night blindness VITAMIN A DEFICIENCY

RETINOID TOXICITY

Hypervitaminosis: dose > 7.5 mg/day

Symptoms:

Skin (dry, pruritic)

Liver: enlarged  cirrhotic liver disease

CNS: intracranial pressure

Pregnancy: teratogenesis, increases the risk of bone fractures

Contraindication for isotretinoin: pregnancy

Prolong use of isotretinoin: increases TAG, cholesterol

Requirement: Male: 900 retinol activity equivalent (RAE) Female: 700 RAE Pregnancy: 3000 μg preformed vit. A/day 1 RAE = 1μg of retinol = 12 μg of β-carotene = 24 μg carotenoid

VITAMIN D

Sterol: hormone-like function

Function: regulate Ca

2+

, phosphorus (PO

4 3 -

Vit. D Vit. D 25 - hydroxyl- cholecalciferol 1,25-dihydroxyl- cholecalciferol 1 - hydroxylase In liver 25 - hydroxylase In kidneys (Calcitriol)

VITAMIN D DEFICIENCY

NUTRITIONAL RICKETS RENAL OSTEODYSTROPHY

RICKETS OSTEOMALACIA

Collagen matrix no mineralization Cause:

• in Northern latitude
• Mutation of vit. D receptor Chronic kidney disease Active form vit D Phosphorus Hyperphosphatemia Hypocalcemia PTH Bone? Ca 2+ and PO 4 3 - ?

Treatment: vit D supplement

TOXICITY Only in supplement High dose: 100000 IU/week or month  metastatic in calcification Symptoms: loss of appetite, nausea, thirst, weakness

VITAMIN E DEFICIENCY NEWBORNS ADULTS Very low birth weight infants Hemolysis Retinopathy Vit E prevents Abetalipoproteinemia Def. of chylomicrons, VLDL Vit E def. CLINICAL USE Vit E and C: age-related macular degeneration TOXICITY Less toxic Dose 30-1000 mg/d

Hydroquinone (^) Epoxide form VITAMIN K CYCLE Glutamic acid residue gamma-carboxyl glutamate residue Note: carboxylation of proteins